Tricking the search engines just does not work. The search engines do not look kindly upon webmasters who attempt to deceive the search engines about the content contained on a webpage.
1. Cloaking
Cloaking a website is a stealth technique used to provide a copy of a web page to search engines while providing an alternate copy to website visitors. The website copy provided to the search engine is optimized and not always reflective of the real content contained on the webpage.
2. Hidden Text
Another deceptive tip that will result in a search engine ban, is done by incorporating text into a website that is not visible to the naked eye, but is visible to search engine spider. There are two ways that underhanded webmasters might attempt this, the first is by changing the font color to match the web page's background color. The second fallacious way of deceiving the search engine using hidden text is by using a single character like a '.' period as a link. Black hat webmasters might attempt this as a way to increase their websites link popularity.
3. Bad Links
While this is not as much a deceptive practice as an indication that the webpage content has been abandoned, links to webpages that no longer exist is an indication to search engines that the content is no longer relevant.
4. Lack of Meta Tags
A website that does not make use of title and description tags, will not result in a ban but could impact the ability for a website to rank well. The title and description of a website should be different on each and every web page.
5. Navigation Mistakes
Navigation should be "spiderable". Do not use javascript or flash navigation, search engines can not spider javascript menus. Adding a site map link is just not good enough, if you do not use conventional navigational techniques, the pages within your website will not always be indexed by the search engines. Navigation should be logically structured, links should not be hidden too deeply within the website or the content contained on the buried pages will not be considered relevant and will not rank well.
6. Valid Code
Observing the conventions of HTML are a necessity, if a webpage's code is invalid, search engines might 'choke' and be unable to follow the links or code. Be sure to properly open and close all HTML code. Valid HTML is critical.
7. Keyword Stuffing
Keyword stuffing is a technique where a long list of repetitive keywords, sometimes related sometimes unrelated to the webpages content is used to trick search engines into thinking the webpage is relevant. Rarely is this effective and it is unlikely that it will artificially inflate a websites ranking for any length of time.
8. Avoid Session IDs
Webpages within a website that uses session IDs or "ID=" in the links will not always be recognized by search engines. It is assumed by many search engines that when ID= appears in the URL, that the webpage does not contain unique content and that the webpage is not in need of indexing. Avoid using ID= on dynamic or static web pages.
9. Nice Neighbors
Avoid listing the website in link farms. Search engines are firm believers that you are like the company that you keep, links should be solicited from reputable sources. Links from spammy websites will not help a website rank well.
Many will say that there are no rules to search engine optimization, they might be right, but the fact remains that webmasters can influence their search engine ranking through the tips above. Attempting to trick or fool the search engines is a sure fire way to become banned. Search engines have the ability to provide a consistent and steady stream of traffic to websites, that stream can become a trickle if you attempt to deceive.
Source : http://www.goarticles.com